EMD "F7" Diesel Locomotives

Last revised: February 19, 2022

By: Adam Burns

The F7 was the Electro-Motive's four entry in its line of freight service locomotives and proved to be one of the most successful designs of any type ever built.

The model debuted directly after the F3 in the late 1940s and with EMD's success in the market up to that point railroads quickly placed orders for the F7. Once again, the latest F model proved efficient, rugged, and easy to maintain.   

Before production had ended on the F7 nearly 4,000 units were produced outselling all other manufacturers' designs, combined. The F7 proved so reliable and useful for many roads that hundreds remained in regular freight service through the 1970s and 1980s. 

Today, numerous F7's remain preserved (partially due it being the last model of its kind manufactured on a large scale) and some even continue to haul freight, a true testament to their design. The most famous set (a pair of B units) is the fleet owned by Class I Norfolk Southern used as part of its official business train.

The EMD F7 began production in February of 1949. Internally, the model varied slightly from the F3 as it still carried GM's 16-cylinder, model 567B prime mover which could produce 1,500 horsepower.

It did use a slightly updated generator, the model D12B, and traction motor, the model D27C, first used on the "F5", which was technically a late model F3 (EMD did not distinguish the locomotive as an F5, instead referring to the slight variants as phases).

The new traction motor was meant to be more rugged and durable than the previous.  However, it continued to offer the locomotive the same tractive effort as the earlier F3; 56,500 pounds starting and 40,000 pounds continuous. Using a similar frame design as the F3, F2, and FT the F7 was just over 50 feet in length and weighed 115 tons.  

Once again railroads very much liked EMD's latest F model and many which had yet to fully dieselize did so after their F7 orders were completed (wartime restrictions had still held back some lines from either starting or completing their change over to diesel power).

The model was easy to maintain and very reliable; coupled with a matching 1,500 horsepower cabless B unit a set of F7s could double a train's power to 3,000 hp (in theory you could equip as many Fs to a single train as you wished, whether at the head-end or cut-in throughout the train).

While intended for use in freight service, with their clean, streamlined design many F7s also found their way into passenger service alongside E units (notably on the Santa Fe which sometimes featured Fs on trains as posh as the Super Chief and El Capitan). 

Generally, the locomotive was equipped with a 62:15 gear ratio for freight service, offering a top speed of around 65 mph.  However, for passenger assignments they were geared for higher speeds. 

As with the F3, EMD slightly upgraded the F7's carbody during its production run although most changes were primarily focused on the grille area.

The EMD F7 was the SD40-2 of its day, the first true "common" diesel locomotive; thousands were built and could be found powering almost any train. When production had ended some 2,366 F7As and 1,483 F7Bs had been produced by 1953 just four years after the locomotive was first cataloged.  

According to an article by Don Strack, published in the November/December 1991 issue of "Diesel Era: Volume 2, Number 6" the, "base price on two cab units was $161,000 and the base price for two booster units was $147,500."  

This was also the first instance of the Electro-Motive Division's new General Motors Diesel (GMD) subsidiary filling orders. Located in London, Ontario, the new plant made it much easier to sell locomotives to Canadian lines. 

In all, GMD sold 127 examples to the Canadian National, Canadian Pacific, and the Wabash for its line in southern Ontario between Detroit and Niagara Falls/Buffalo, New York. The model was EMD's most successful in the F series as no other future design ever came close to matching the F7's sales numbers.

EMD F7A Production Roster

Owner	Road Number(s)	Quantity	Date Built
Alaska Railroad	1500-1508 (Evens)	5	1952-1953
Atlantic Coast Line	348-429	82	1950-1951
Baltimore & Ohio	180-192, 180A-192A (Evens), 231-237, 239-374, 239A-365A (Odds), 929-993, 929A-993A (Odds)	144	1949-1952
Bessemer & Lake Erie	701A-728A	28	1950-1953
Boston & Maine	4265-4268	4	1949
Burlington	163A-169A, 167C-169C	10	1950
Charleston & Western Carolina Railway	900-905	6	1950
Chesapeake & Ohio	7000-7085	86	1950-1952
Chicago & North Western	4067A-4102A, 4067C-4102C, 6500A-6505A, 6500C-6505C	84	1949- 1950
Chicago Great Western	153-156	4	1949
Clinchfield Railroad	806-820	15	1951-1952
Colorado & Southern Railway (CB&Q)	700A-702A, 700D-702D	6	1950
Denver & Rio Grande Western	555-564, 5651-5764 (Only 1s and 4s.)	67	1948-1952
Electro-Motive (Demo)	459A, 459D, 801-802, 930, 1950A, 1950B, 5040	8	1949-1952
Erie Railroad	711A-712A, 711D-712D, 807A, 807D	6	1950-1951
Fort Worth & Denver City (CB&Q)	750A-752A, 750D-752D	6	1950
Great Northern	268A-274A, 271B-275B, 275A-276A, 280A-281A, 307A-317A, 307C-317C, 350A, 360A, 364A-365A, 364C-365C, 444A-456A (Evens), 444D-456D (Evens), 460A-468A (Evens), 460D-468D (Evens)	68	1949-1953
Gulf, Mobile & Ohio	811B-812B, 812A-813A	4	1949
Kansas, Oklahoma & Gulf Railway	751-754	4	1949
Kansas City Southern (Including Subsidiaries)	32A-33A, 59D, 70A-76A, 72D-76D	15	1949- 1950
Lackawanna	611A-611C, 631A-636A, 631C	9	1949
Lehigh Valley	560-574 (Evens)	8	1950-1951
Louisville & Nashville	800-858, 900-903	63	1950-1951
Nashville, Chattanooga & St. Louis	809-831	23	1949-1951
Milwaukee Road	48A-50A, 48C-50C, 68A-89A, 84D-85D, 68C-79C, 87C-89C, 106A-111A, 109C-111C, 113A-121A, 113C-121C	68	1949-1953
Minneapolis & St. Louis Railway	150A-151A, 150C-151C, 250A, 250C, 350A, 350C	8	1949- 1950
Missouri-Kansas-Texas Railroad (Katy)	208A-211A, 226A-229A, 208C-211C, 228C- 229C	14	1949
Missouri Pacific (Including Some Subsidiaries)	577-626, 1500-1582	133	1949-1951
Nashville, Chattanooga & St. Louis	816-820, 826-831	10	1950-1951
New York Central	1636-1873	238	1949-1952
Northern Pacific	6007A-6020A, 6007D-6020D, 6507A-6508A, 6500C-6502C, 6509A-6515A, 6507C- 65013C	47	1947-1951
Pennsylvania	9640A-9655A, 9662A-9676A, 9690A-9699A, 9764A-9831A, 9872A-9879A	117	1949- 1952
Reading	266-283	18	1950
Richmond, Fredericksburg & Potomac	1101-1110	10	1949-1950
Rock Island	100-127, 675-677	31	1949-1951
Santa Fe	37-47, 37C-47C, 200L-280L, 200C-280C, 202-280, 300-316, 336-344, 300L-314L, 325L- 344L	324	1948-1953
Soo Line	212A-214A, 212B-214B, 2201A-2203A, 2201C-2203C, 2224A-2230A (Wisconsin Central), 2224B-2230B (Wisconsin Central)	26	1949-1953
Southern Pacific	338-381 (T&NO), 6140A-6169A, 6140D-6169D, 6240-6423, 6440-6445	288	1949- 1953
Southern Railway (Including Subsidiaries)	4207-4269, 6114-6120, 6714-6719	65	1949- 1951
Spokane, Portland & Seattle	803-806	4	1953
St. Louis San Francisco Railway (Frisco)	5018-5039	22	1949-1950
St. Louis Southwestern Railway (Cotton Belt/SP)	925-975 (Odds)	26	1950-1952
Texas & Pacific Railway (MP)	1500-1582	83	1949-1952
Texas-Mexican Railway	800A-800B	2	1949
Wabash Railroad	1100-1108, 1100A-1108A, 1140-1154, 1140A-1154A, 1165-1188, 1165A- 1188A	96	1949-1953
Western Maryland	53-66, 231-242/td>	26	1950-1952
Western Pacific	913A-924A, 913D-924D	24	1950-1951

EMD F7B Production Roster

Owner	Road Number(s)	Quantity	Date Built
Alaska Railroad	1501-1507 (Odds)	4	1952-1953
Atlantic Coast Line	392B-403B	12	1951
Baltimore & Ohio	153x-171x (Odds); 180x-192x, 180Ax, 192Ax (Evens); 231x-237x (Odds); 249x-297x (Odds); 361x, 363x, 363Ax, 365x, 365Ax; 367x-374x, 367Ax-374Ax; 929x-961x (Odds); 977x-993x (Odds)	100	1949-1953
Bessemer & Lake Erie	701B-726B	26	1950-1953
Boston & Maine	4265B-4268B	4	1950
Burlington	167B-169B	3	1950
Chicago & North Western	4067B-4094B	28	1949-1952
Chicago Great Western	113B-116B, 108D-116D, 116E, 116F, 116G	16	1949-1951
Clinchfield Railroad	853-863	11	1949-1952
Colorado & Southern Railway (CB&Q)	700B-702B, 700C-702C	6	1950
Denver & Rio Grande Western	555-564, 5652-5762 (Only 2s and 3s.)	66	1949-1952
Electro-Motive (Demo)	459B, 459C, 7002-7003, 9052-9053	6	1949-1952
Erie Railroad	711B-712B, 711C-713C, 807B	6	1950-1952
Fort Worth & Denver City (CB&Q)	750B-752B, 750C-752C	6	1950
Great Northern	268B-270B, 280B-281B, 307B-309B, 311B-317B, 350B, 364B-365B, 380B-385B, 444B-468B (Evens), 444C-468C (Evens), 500B-504B	45	1949-1953
Gulf, Mobile & Ohio	B65-B74	10	1949-1950
Kansas, Oklahoma & Gulf Railway	755B-756B	2	1949
Kansas City Southern	32B-33B, 70B-79B, 72C-78C	17	1949-1950
Lackawanna	611B, 632B-636B	6	1949
Lehigh Valley	561-571 (Odds)	6	1950-1951
Louisville & Nashville	703-716, 900-902	17	1950-1951
Milwaukee Road	48B-50B, 68B-79B, 84B-85B, 87B-105B, 109B-111B, 113B-121B, 84C-85C	48	1949- 1953
Missouri-Kansas-Texas Railroad (Katy)	65D-65G, 121B-124B, 207B	9	1949
Missouri Pacific (Including Some Subsidiaries)	587B-596B, 629B-630B, 1500B-1534B	47	1949- 1951
Nashville, Chattanooga & St. Louis	912-919	8	1949-1950
New York Central	2420-2474	55	1949-1951
Northern Pacific	6007B-6020B, 6007C-6020C, 6050, 6510B-6513B, 6550	34	1949-1952
Pennsylvania	9547B-9555B (Odds), 9640B-9648B, 9650B-9660B (Evens), 9667B-9676B, 9764B-9818B (Evens), 9832B-9858B (Evens), 9872B-9878B (Evens)	76	1949-1952
Reading	266B-271B	6	1950
Richmond, Fredericksburg & Potomac	1151-1160	10	1949-1950
Rock Island	100B-109B, 120B-123B, 675B-677B	17	1949-1951
Santa Fe	200A-280A, 200B-280B, 300A-314A, 300B-314B, 325A-344A, 325B-340B	228	1948- 1953
Soo Line	500B-503B, 2101C-2203C (WC), 2204C (WC), 2500B-2501B (WC)	10	1949-1952
Southern Pacific	538-553, 6140B-6169B, 6140C-6169C, 8140-8303	240	1949-1953
Southern Railway (Including Subsidiaries)	4385-4428, 6160-6183, 6756-6758	71	1949- 1951
St. Louis San Francisco Railway (Frisco)	5118-5139	22	1949-1952
St. Louis Southwestern Railway (Cotton Belt/SP)	926-958 (Evens)	16	1950-1952
Texas & Pacific Railway (MP)	1500B-1534B	35	1949-1952
Union Pacific	910B, 910C, 1466B-1474B (Evens), 1466C-1474C (Evens), 1476B-1496B, 1476C-1496C	33	1951-1952
Wabash Railroad	1100B-1108B	9	1949-1950
Western Maryland	53B-59B, 61B-65B (Odds), 231B-237B, 239B-243B (Odds)	20	1950-1953
Western Pacific	804B-805B, 913B-924B, 913C-924C	26	1950-1951

The EMD F7's reliability and ruggedness can still be seen today as dozens remain preserved and in operation with a handful still work freight trains, notably on short line Grafton & Upton (now stored) and Keokuk Junction Railway (two FP9A's and an F9B).

Other places one can still find F7s in use include:

• Conway Scenic Railway


• Reading Company Technical & Historical Society


• Adirondack Scenic Railroad


• Royal Gorge Railroad


• Illinois Railway Museum


• Potomac Eagle Scenic Railroad


• Fillmore & Western

The most famous F7s pulled Norfolk Southern's business train for many years, featuring a livery inspired by predecessor Southern Railway. The units have since been sold: F9A #270 and F7B #275 were purchased by Reading & Northern on November 23, 2019 for passenger service. 

Just a few weeks later it was announced on December 13, 2019 that North Carolina short line Aberdeen Carolina & Western would acquire F9A #271 and F7B #276. 

1. Home
 ›
2. Diesel Locomotives
 ›
3. F7